The invention described herein may be manufactured, licensed, and used by or for the U.S. Government.
The present invention relates generally to respiratory masks, more particularly to full-face respiratory masks adapted for protecting the wearer against biologically/chemically hazardous materials especially in the form of airborne particulates, vapors and aerosols.
Respiratory masks that are adapted to protect the wearer""s face, eyes, and lungs from the effects of hazardous airborne particles of a chemical or biological nature were first used to protect soldiers during war against poison gases. Today such masks have evolved and developed for use in many capacities, including, but not limited to firefighting, environmental cleanup, manufacturing, medical hazard handling, quarantining of patients with highly contagious pathogens, biological and chemical warfare, mining, paint applications, construction, and other applications where persons may come into contact with hazardous substances especially those of airborne nature.
Typically, the mask is worn over the wearer""s face sealed from the ambient atmosphere and cleans the air entering the mask by means of a filter device generally comprised of chemically impregnated fibers or a bed of adsorbent material usually activated charcoal. During operation, a one-way inlet valve in the mask allows air drawn in by the wearer""s lungs into a filter containing the absorbent material, whereby the filtered air then flows into the mask. Thus, the air is filtered and cleaned as it enters the mask. As the wearer exhales, the exhaled gas is expelled through a one-way exit valve out of the mask and the process is repeated with each breath.
Full-face respiratory masks are typically uncomfortable and difficult to wear for long periods of time and impose significant burden on the wearer. Such masks are typically heavy and bulky, restrict vision, generate heat stress and discomfort for the wearer, difficult to breathe through, and trap moisture vapors and perspiration causing lens fogging and discomfort. In addition, when the masks are not worn, they are cumbersome to carry and often cannot be folded without damage into a compact form.
For the foregoing reasons, there is a need for a full-face respiratory mask useful for protecting the wearer against hazardous chemical and biological agents in the form of aerosols, vapors and the like, while maintaining long-term wearability, improved long-term chemical and biological protection, and capacity to be packed into a small compact package. The full-face respiratory mask of the present invention as described herein overcomes the shortcomings described above.
The present invention provides a respiratory mask assembly for protecting a wearer from biological and/or chemical agents that may be present in an atmosphere. The respiratory mask of the present invention provides a military level of protection against biological and chemical agents over a long period of time without similar level of burden and discomfort often associated with full-face mask configurations. The respiratory mask is configured to be highly compact and portable so that it may be conveniently carried and/or packed into a tightly compact hermetically sealed package prior to wear. The mask is easily manufactured using inexpensive and readily available component parts and equipment. In addition, the design of the mask provides the wearer a wide unobstructed field of vision while allowing the wearer to effectively communicate with others. The mask is further adapted to minimize moisture-related fogging and accumulation of carbon dioxide in the interior thereof and facilitate the dissipation of heat and perspiration unavoidably generated by the wearer, while providing a high level of chemical/biological protection suitable especially for military use.
In one aspect of the present invention there is provided a respiratory mask assembly for filtering airborne biological and/or chemical agents from air for breathing, which comprises:
an outer hood adapted to seal with and encompass at least the head and neck of a wearer from ambient atmosphere;
at least one transparent lens attached to the outer hood for providing visual sight to the wearer;
at least one filter assembly attached to the outer hood, the filter assembly adapted for filtering airborne biological and/or chemical agents from air passing therethrough;
an airflow regulator located in the outer hood, the airflow regulator including an outlet adapted for expelling exhaled air to ambient, and an inlet adapted for drawing air thereinto; and
air conveying means located in the outer hood for conveying air filtered through the filter assembly from ambient to the inside surface of the transparent lens for drawing into the airflow regulator inlet.